Correcting vignette with GIMP

Discussion in 'Digital Darkroom' started by martin_altmann, Jun 17, 2005.

  1. I have a set of slides taken back in 1998 with my Nikon F401 camera
    mostly taken with my then new 24 mm Nikkor lens. Unfortunately I was
    using two filters - being unaware that this causes vignette (well of
    course I know about the principal problem but the viewfinder did not
    show any - it hasn't got 100% - the 35-70 kit lens did not show
    vignette with two filters (UV+Cpol)). So many of those pics ended up
    with having quite severe vignette effects. Some of these have been
    scanned by me in the meantime, now I'm looking for a way to correct
    this flaw using my standard software GIMP. Since I right now have
    access to LINUX only PS is not an option. Searching the internet I
    found many tips on how to add a vignette to a picture with GIMP, but
    that is not what I wanted, i want to flatten my vignetted pics - no
    information found. If anybody knows how to do it under GIMP, I would
    be glad if you could share this information. Thanks.
     
  2. You could try the panorama tools. You can download it from http://www.vierpi.de It's bit tricky to use, but can do amazing things.

    -matti
     
  3. I think the same folks (Panorama Tools) make PTLens - I believe it's got a vignette-fixing feature. It's easy as pie - and free!
     
  4. Hi Martin .. Here is what I just tried: Add a layer on top of your image, use the gradient tool to draw a radial black-to-white pattern on it, then change the layer blending mode to "Burn", and you will get an effect that lightens the edges of the frame. This is crude but it is a place to start, and you can probably get what you want by experimenting with the other blending modes and maybe reducing the later opacity.

    Of course if the vignetting is so bad that the pixels outside the circle are just black, there's nothing you can do but crop them out.

    Nice to see there are other Gimp-y people out there..
     

Share This Page